China's Internet giant Tencent has sued the country's Trademark Review and Adjudication Board (TRAB) after its application to trademark QQ's beeping sound was rejected by the latter.

Tencent QQ, one of the most popular instant messaging software services in China, applied to register the signature "Di-Di-Di-Di-Di-Di" notification sound as its trademark in 2014, which is permitted by China's Trademark Law as long as the sound can be easily distinguished. Tencent's application was later turned down by TRAB, with the explanation that the sound was "simple and not creative," lacking in any distinctive traits.

"We have checked many sound trademarks approved by other nations, including the famous lion roar of Metro-Goldwyn-Mayer. Most sound trademarks last less than five seconds and are quite simple. By TRAB's standards, they also could not be registered as trademarks," said Huang Yibiao, a lawyer for Tencent, during the court hearing on Dec 6.

According to Huang, due to QQ's popularity in China, the public has already connected the beeping sound with QQ's services, which means it does possess distinctiveness. TRAB, on the other hand, holds a different opinion. It reiterated that Tencent's notification sound is merely a repetition of notes, which is not distinctive at all. According to TRAB, the board is very careful about approvals of sound trademarks, with few successful cases so far. The court will release its final verdict at a later date.

Tencent's accusation has stirred up online debate, with some netizens supporting the company's appeal and others calling it a joke.